Added a -q option to suppress output if no errors was found
rewrite parameter parsing so options can come in any order
Shows name of file on error
improve error position marker slightly

before:
  $ bin/jsonlint bad.json
  bad.json: Parse error on line 2:
  ...th trailing comma",}
  ----------------------^
  Expected: 'STRING' - It appears you have an extra trailing comma

after:
  $ bin/jsonlint bad.json
  bad.json: Parse error on line 2:
  ...th trailing comma",}
  ---------------------^
explicitly show usage when invoked with -h or --help,
fixing broken code path where usage info was displayed
only if file_get_contents('php://stdin') failed, which is
not possible
Merge remote-tracking branch 'martinlindhe/master'